Ultra short wave attenuator and directive device



July 2, 1940. v l. WOLFF 2,206,683

ULTRA SHORT WAVE ATTENUATOR AND DIRECTIVE DEVICE FiledMay 16, 1936 Gene/"afar sectional view Patented July 2, 1940 PATENT OFFICE ULTRA snon'rwAvE ATTENUATOR AND m mc'rlvn DEVICE Irving Wolfl', Merchantville, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application May 16, 1936, Serial No. 80,120

12 Claims.

My invention relates to an ultra short wave attenuator and directive device. Specifically, my invention is an ultra short wave generator, .which radiates through an attenuating device, and the radiation is, thereafter "beamed or directed.

I am aware of the use of electrical networks for attenuating radio frequency currents. Such networks are not entirely suitable at ultra high frequencies. Reflectors for antennas have been used to direct the radiation. The present invention makes use of the similarity of wave length of sound and ultra high frequency waves. The ultra high frequency waves are controlled and directed by means which are similar to those employed in the control of sound waves.

One of the objects of this invention is to control the strength of an ultra high frequency wave. Another object is to beam or direct the radiation from an ultra high frequency device. A further object is to provide a device which may be used to determine the relative field strengths of ultra high frequency waves.

In the accompanying drawing, Figure 1 is a of one embodiment of my invention,

Figure 2 is a plan view of a variable opening attenuator used in Figure 1,

Figure 3 is a perspective view of one form of sectionalized beaming device,

Figure 4 is a perspective view of a variable opening flare or beaming device, and

Figure 5 is a schematic diagram illustrating apparatus for measuring the energy of the radiated wave.

Referring to Figure 1, a generator of ultra high frequency currents is represented by the block diagram 1. This generator may be any of the. well known electronic oscillators; such as a magnetron, Barkhausen-Kurz, or the like. The generator I is connected to a dipole antenna 3 by a transmission line 5. A suitable reflector 1 may be disposed behind the dipole antenna.

The generator, transmission line, antenna, and reflector are enclosed within a shielded box 9. which may be made of copper or any suitable conductive material. A hollow cylindrical conductor I l is secured in the side of the shielded box 9, opposite to and coaxially disposed with respect to the reflector 1. A variable opening attenuator I3 is pivotally mounted on a stud l5, and rotatablyarranged within the conductive member If through a slit IT. The conductive member may be reinforced adjacent the slit by any suitable means. vided with a series of opemngs M of different diameters, which may be successfully positioned within the conductor II.

A second hollow cylindrical member I9 is 5 slidably mounted tenna 3. By choice of attenuator openings, the the dipole antenna, radiated through the opening into the hollow conductive member, may be varied or controlled. The largest opening attenuates slightly, while the 15 smaller openings attenuate greatly. Ina similar manner, the length of the hollow cylindrical conductor between the'antenna and the flared member may be regulated to determine the attenuation of the radiated energy. The flared portion 2| at the end of the hollow conductor determines the directive or beam effect of the radiated energy. If the wave length is short with respect to the diameter of the flared portion, a sharply formed beam may portion of the attenuator to more sharply beam the wave. A suitable sectionalized flare is illustrated in Fig. 3. In a like manner, the flare may be ad justed by increasing or decreasing its larger diameter, as indicated in Fig. 4. The corrugated portion 23 at the base of the flare offers suflicient flexibility to permit such adjustment.

A means of measuring the energy of the radiated wave is illustrated in Fig. 5. A dipole antenna 25, preferably of the same length as the transmitting antenna 3, is connected to a thermocouple 21. The thermocouple is mounted Within an evacuated envelope 29. A pair of radio frequency choke coils 3|, 3| are connected to the thermocouple and to a suitable galvanometer 33. The dipole 25 and associated thermocouple 21 may be positioned adjacent the transmitting antenna. within the shielding box 9. Thus arranged, the radiated energy may be measured before attenuation. The propagation of the attenuated wave may be directed or beamed as previously described.

demodulator 'whichis in turn coupled to a. signal indicating instrument. The received'siggals. maybe collected :by appropriately directing the flared portion 2| and attenuation is effected as in the case of a transmitter.

, be constructed as illustrated, but the use of? an opening the area of which may be continuously varied is within the scope of my invention.

I claim as my invention:

1. An ultra high frequency device comprising an antenna, means for shielding said antenna, a hollow conductor secured to said shielding means and exposing said antenna, a second hollow conductor slidably mounted on said first conductor, a flared portion mounted on said second hollow conductor for imparting a beaming effect on radio energy passing therethrough, and means including said flaredportion for adjusting the sharpness of said beam.

2. In a device of the character of claim 1 means for adjusting the effective length of the hollow conductor disposed between said shield and said flared portion.

3. In a device of the character of claim 1 means disposedwithin one of said hollow conductors for attenuating radio frequency energy passing therethrough.

4. In a device of the character of claim 1 means for adjusting the effective length of the hollow conductor disposed between said shield and said flared portion and means disposed within one of said hollow conductors for attenuating radio frequency energy passing therethrough.

5. An ultra high radio frequency device comprising a wave responsive member, means for shielding said wave responsive member, a hollow conductor of adjustable length secured to said shielding means and exposing said wave responsive means to radio frequency waves, means for adjusting the length of said hollow conductor, means disposed within said hollow conductor member for varying the quency wave energy passed through said hollow conductor, a flared horn, and means including said horn for adjusting the sharpness of the beam of energy radiated therefrom.

6. An ultra high frequency device comprising a wave responsive member, means for shielding said wave responsive member, a hollow conductor amount of radio fref secured to said shielding meansand exposing said wave responsive means to radio frequency waves, means disposed within said hollow conductor member for varying'the amount of radio frequency wave energy passed through said hollow conductor, and. a sectionalized beaming means substantially coaxially and'adjustably disposed with respect to said wave responsive means.

'7. An ultra high frequency device comprising a wave responsive member, means for shielding said wave responsive member, a hollow conductor secured to said shielding means and exposing said wave responsive means to radio .frequency waves, means disposed within said hollow conductor member for varying the amount of radio frequency wave energy passed through said hollow conductor, and means for beaming radio frequency energy comprising a conductor having a flared portion and means for adjusting the larger diameter of said flared portion.

8. An ultra high frequency radio device including a generator of ultra high radio frequency currents, means for radiating said currents, means for shielding said radiating means except for an aperture therein, a horn, means for securing said horn to the shield to thereby substantially surround said aperture, and means for including said horn for adjusting the sharpness of the beam of radio frequency energy radiated through said aperture and said horn.

9. A radio transmitter including a generator of radio frequency currents, a radiator connected to said generator, means for shielding said radiator, said shielding means including an aperture, means for directing radiations from said radiator through said aperture, a horn arranged substantially in alignment with said aperture for beaming said radiations, and means including said horn for adjusting the width of said beam of radiations.

10. A radio transmitter including a generator of radio frequency currents, a radiator connected to said generator, means for shielding said radiator, said shielding means including an aperture, a horn arranged substantially in alignment with said aperture for beaming radiations from said radiator, and means including said horn for predetermining the sharpness of said beam.

ILA device of the character of claim 10 including a plurality of beam sectionalizing elements located within said horn.

12. A device of the character of claim 10 including adjustable means for varying the angle formed by the sides of the horn.

mvma woLFF. 

